This invention relates to amino acid fragments of secretin. Secretin is a hormone secreted by the mucosa of the duodenum and jejunum when acid chyme enters the intestine. Secretin has been isolated, and the amino acid sequence has been described as follows:
______________________________________ His-Ser-Asp-Gly-Thr-Phe-Thr-Ser-Glu- .sup.1.sup.2.sup.3.sup.4.sup.5.sup.6.sup.7.sup.8.sup.9 Leu-Ser-Arg-Leu-Arg-Asp-Ser-Ala-Arg- .sup.10.sup.11.sup.12.sup.13.sup.14.sup.15.sup.16.sup.17.sup.18 Leu-Glu-Arg-Leu-Leu-Glu-Gly-Leu-Val-NH.sub.2 .sup.19.sup.20.sup.21.sup.22.sup.23.sup.24.sup.25.sup.26.sup.27 ______________________________________
wherein the stereochemical configuration of each of the optically active amino acid residues is L.
Secretin stimulates pancreatic secretion of water and bicarbonate. In the stomach, secretin stimulates pepsin secretion, stimulates the pyloric sphincter, inhibits gastrin-stimulated acid secretion, inhibits food-stimulated gastrin release, and inhibits motility. Rayford et al, New England Journal of Medicine, May 13, 1976 (1093-2000).